Insulated screw



June 19, 1928. 1,674,258

H. F. OBERGFELL ErAL INSULATED SCREW Filed June 24, 1925 HUN Imqqsnlnr H 7 HEIZJETI F Ubergmbzni-Juhn LIICKSEF.

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Patented June 19, 1928 lTE *t'i r re ns,

HERBERT l GBERGFELII, 0F 31V ER 'EQRIEST, AND EDEN ERICKSON, OF CHICAGO, IUZL hlOIS, ASSIGNORS, BY MESNE ASSIGNMENTS, TO AUTOMATIC ELECTREG GHEGAGG, ELLINOIS, A GGBPGRAEEON 01* DELAVTARE.

ENG, 01?

dedication filed June as, 1925. serial No. 39,213.

This invention relates in general to insu lated screws, and has for its principal object the provision of an insulated screw in which the insulator and screw are fastened together and may be handled. as an ordinary screw.

Another object of our invention is to provide a metal washer attached to a screw and insulated from it.

A. further object of our invention is to provide an insulated screw in which the insulating assembly is held adjacent to the screw head.

A still further object is to provide an insulated screw of the character set forth in the preceding objects in which the washer and insulating assembly turn fully on the screw.

in the drawings, l igs l and 2 show respectively the completed assembled screw, and the sectional details of its construction, and Fig, 3 shows an exploded view oi the arts 0:6 the screw. Fig. 1 shows an oval nllister head machine screw equipped with an insulating member built in accordance with the object of this invention.

Figure 2 shows the construction details of this screw. l/Ve have taken a ll. S. standard oval iillister head machine screw 1 and turned down a shank 8 directly beneath the head, the diameter of the shank being approximately the root diameter or the screw thread. Around this shank we have fitted an insulating collar l, which is made oi semiflexible material, such as fiber, hard rubber, or balielite composition and which is slit to permit its being slipped over the shank, @ver this insulating sleeve and adjacent to the head or" the screw, we have placed an insulat ing washer 2, which may be made of fiber,

hard rubber, or bakelite composition. The sleeve and washer are held on the screw by means of the eyelet 3, which is pressed on over the collar i and up against the washer 2.

c This collar 3, is not tight enough to bind the insulating sleeve 4 to the shank 8 of the machine screw, but rather leaves the sleeve free to slide over the shank, so that the screw can be tightened without turning the insulator assembly. The member 5 which is being held on the mounting plate '7 by the screw 1, is insulated therefrom by the insulating strip 5g 6 and washer assembly of the screw.

The utility of such a screw as we have designed lies principally in the mounting of electrical equipment, when it is expedient to solidly attach such equipment to suitable base and at the same time to insulate it therefrom.

While we have shown and described a particular form of insulated screw made in accordance with the obfiect or" our invention, we have done so merely by way of example and do not wish to limit ourselves to the specific disclosure of the drawings and specification. The principal of insulating screws in the manner we have, can be applied to a large variety or machine screws, bolts, and wood screws,

Having thus described our invention what we consider new and desire to have protected by Letters Patent is pointed out in the appended claims.

What is claimed is:

1. A screwhavin a threaded portion, a head, and a shank adjacent to said head, the diameter of said shank being approximately the root diameter of said threads, an insulat= ing sleeve placed around said shank, an insu lating washer around said sleeve and adjacent to said head, a metal eyelet over said sleeve and washer, said eyelet, threads and head cooperating to hold said insulating members on said screw adjacent to said head,

2. A screw having a threaded portion, a head, and a shank adjacent to said head the diameter of said shank being approximately the root diameter of said threads, an insulating sleeve placed around said shank an insulating washer around said sleeve and adjacent to said head, a metal eyelet over said sleeve and washer, said eyelet, threads and head cooperating to hold said insulating members on said screw adjacent to said head, said insulating assembly being rotatable around said shank.

3. An article of manufacture comprising a I screw having a head, a shank adjacent thereto, and a threaded portion, the diameter of the shank being approximately the root diameter of said threaded portion, an insulattion assembly comprising an insulating sleeve fitting around said shank and an insulating washer fitting over said sleeve and against said screwhead, and means comprising an eyelet forced over said sleeve and against said washer for holding said screw and insulator assembl to ether as a unit.

In witness whereo I ereunto subscribe my name this 17th day of June, A. D; 1925.

HERBERT F. OBERGFELL. In witness whereof, I hereunto subscribe my name this 17th day of June, A. D. 1925.

, i JOHN ERICKSON. 

